New Enzyme Trial

During a recent meeting of the European Study Group of
Lysosomal Disorders in Oslo during September 2005, Prof Ari Zimran from
the Gaucher Clinic at Shaare Zedek Medical Center presented the six months
results from the Phase I/II clinical trial of a new enzyme preparation for
patients with Type I Gaucher disease produced by Transkaryotic Therapeutics
(TKT) which is now owned by Shire Pharmaceuticals.

'The new enzyme was developed by TKT using the company's
proprietary gene activation technology, and is called "gene-activated human
glucocerebrosidase" (GA-GCB) reports Prof Zimran'. 'GA-GCB has an amino acid
sequence identical to the naturally occurring human enzyme, and this is in
contrast to Cerezyme, which has a single amino acid change at position 495
(histidine instead of arginine). GA-GCB also has terminal mannose residues that
target the enzyme to macrophages, the primary target cells in Gaucher disease.

'The aims of the study (like any Phase I/II trial) were
to evaluate the safety and efficacy of GA-GCB in adult patients (age 18 years
and above) with Type I Gaucher disease. Twelve patients (7 females and 5 males)
enrolled in the study to receive GA-GCB every other week for a total of 40
weeks (20 infusions). Patients either had not received any Cerezyme or had not
received medication for their Gaucher disease for at least one year prior to
treatment with GA-GCB. One patient withdrew consent after three infusions for
reasons not related to treatment. All patients tolerated treatment well at 60
U/kg after 6 months and infusion reactions and adverse events were mild and
transient. No antibodies (to the infused enzyme) were detected in any patient.

'Hemoglobin and platelet levels, spleen and liver
volume, and disease biomarkers were evaluated after six months of GA-GCB
treatment. Mean hemoglobin increase was 1.9 g/dL (all patients increased by
more than 1 g/dL) and the mean platelet count increased by 23.4%. Liver and
spleen volumes were studied by MRI and analyzed as multiple of normal organ
volumes.'

Six months of treatment with GA-GCB showed a
statistical significant reduction of the liver and spleen volumes. In addition,
mean levels of the disease biomarkers chitotriosidase and CCL18 decreased
coincident with the improvements in hematologic parameters and organomegaly'.

Prof Ari Zimran (Principle Investigator) and Dr Deborah
Elstein (Study Co-ordinator) said that 'These results are similar to those
published in the trials of Ceredase and Cerezyme, although, in the current
study (unlike the former ones) no children (patients younger than 18 years of
age) were enrolled. The results suggest that GA-GCB, if approved, could provide
an alternative therapy for patients with Gaucher disease'.